We use international comparison data of Summers and Heston to trace the development of three regions in Western Europe: the countries currently outside the European Union (EEC), the EEC Center, and the EEC Periphery (Greece, Ireland, Portugal, and Spain). For each year during the period 1950-1990, the per capita gross domestic products of these regions decrease in this order, but the development over time shows a rapid increase of all three regions as well as a mutual convergence, the inequality of the regions and their constituent countries declining substantially.